Why did this happen?

Observations with numerous telescopes, space and planetary probes show us ancient river floodplains, seabeds, silt deposits and other water landmarks. But Mars was born with a serious flaw: The planet is very small, only 11% of the mass of Earth. This means that its core is cooling very quickly by cosmic standards.

Part of the heat of the planets arises inside them as a result of the decay of radioactive elements present in the primitive gas cloud that formed the Solar System during the formation of a new body.

Planets also store heat from the formation process itself: each is the result of the compression of a large cloud of dispersed gas and dust into a relatively compact volume. This collapse causes friction, which produces heat. This heat remains inside the planet’s body during its formation and then radiates outward..

There is still a lot of heat on Earth for two reasons:

• First, our planet is larger than Mars and therefore received more heat during its formation.
• Secondly, our planet’s heat is contained in the volume of its body, but only its surface can radiate heat. If you double the size of a planet, its surface area quadruples and its volume increases eightfold. Larger planets radiate heat more slowly than smaller planets.. In other words, we are much less efficient at dissipating heat than Mars.

The Earth’s heat is also maintained by the molten core that creates the magnetic field. The magnetic field keeps the atmosphere safe by repelling the onslaught of deadly solar wind and radiation. Without this protective field, it would fly away.

This was the problem with Mars: Because the planet is so small, over more than a billion years its core has cooled and hardened, and its magnetic field has weakened.. Without this protection, Mars lost its atmosphere, and the water on its surface evaporated under the influence of solar winds and flew into interplanetary space in the form of gas.